I've been thinking of ways to "fix" the hardcoded effects of trade fleets. The problem is (and correct me if I'm wrong!), that from the trading port building complex, the first 3 give you a trade fleet in a hardcoded manner. The first level gives you one trade fleet, second gives you two and the third gives you three. The extra trade fleets that would be given in the EDB don't work. In EB, the first building is the Coastal Clearing building, which shouldn't give you any trading fleets, but in reality due to hard coding, it gives you one.

As a solution, I've been thinking that the "Coastal Clearing", "Small Port Upgrade" and the "Great Port Upgrade" could be moved to the river_port complex. The actual River Port building wouldn't conflict with the seaport buildings, as you cannot have a river hidden_resource at a coastal region.

So first you would have to build Coastal Clearing, which now doesn't give trade fleet, to build the first level port. Then if there is natural harbor, you can build the 2nd level port. If not, you have to build the Port Upgrade building, to be able to upgrade your actual port from level 1 to 2.

Is this possible to do, and could it be added in EB 1.2 for example? I don't have time now, but I might try making a mini-mod which does this, assuming it is possible to do without CTDs or other errors.